PU sole for shoes

ABSTRACT

The present invention is aimed to provide a shoe sole partly made of PU. The object is realized by a shoe sole having a woven surface layer attached to the surface of an EVA based base layer; a shaped hole formed through the base layer, a PU based air permeable portion filled in the shaped hole; the surface layer and PU based air permeable portion are glued together with the EVA based base layer integrally as a whole. An air permeable portion is mainly located at the middle portion to improve the air permeability thereof. The foot of the user can keep dry and more comfortable by improved air permeable portions. The present invention also has stable structure, prolonged lifetime without deformation by partly adopted PU material. It is beneficiary and advantageous for manufacturers adopting the present invention to guarantee the quality of shoe products.

FIELD OF THE INVENTION

The present invention is related to the technique and products about manufacturing shoes, particularly to a sole partly made of PU.

BACKGROUND OF THE INVENTION

Most people are devoted to design a sole with permeability, durability and cost-effective. From conventional sole such as stitching across a canvas strap sole to kinds of modern soles; various modifications about sole materials, sole styles are on sale in the market. R&D focuses on shoe sole seems never stop. For example, Chinese pending patent application no. 86100267 “shoe sole” assigned to Carl Freudenberg & Co. in Germany published on Dec. 3, 1986. It disclosed a shoe sole includes an absorbent layer made of absorbent fibers, and a surface layer secured on top of said absorbent layer. The surface layer is made of woven material with liquid permeability. In which, a layer (1) made of water-repellent fibers, these water-repellent fibers coiled around and threaded through the surface layer to the capillary vessels of an absorbent layer.

Accompanied by the progress of the Chemistry Engineering Industry, shoe soles can be made from plastics, like the sole of the sneaker, most of the soles are mainly made from EVA or PU. It is expected that tiny pores of the foam like plastics shoe sole to improve the air permeability of the shoe sole.

EVA is known popular like “finished India rubber” in Chinese language. A scientific name for EVA is Ethylene-Vinyl Acetate. And the PU is the abbreviated name of a scientific name Polyurethane. As the EVA material exhibits many unique foam-like pores with softness, oil resistant, low thermal conductivity and ideal flexibility so that most shoe soles are made of EVA in recent years. But EVA based shoe soles still has some shortcomings. First of all, the hardness of EVA is insufficient to resist the time-dependent creep so that the EVA will be easily deformed and out-of-shape or shorten its lifetime. Secondly, low air permeability of the EVA may cause beriberi, the user being suffered discomfort after a long time slip-on shoes with EVA sole inside. But, after processing PU through hardened treatment, a hardness of polyurethane foam and the like can be used instead of said EVA. Besides, after processing PU through hardness treatment, it is expected that the compressibility, heat-resistant, dimension stability and air permeability are improved for the finished PU rather than said EVA. More manufacturers adopted the finished PU for manufacturing shoe soles. But the PU is more expensive than the EVA. In manufacturing, the material cost is raised due to the finished PU must be processed through hardened treatment. It results in the loss of competitive ability in the market.

SUMMARY OF THE INVENTION

Accordingly, the primary object of the present invention is to provide a cost-effective, durable and air permeable shoe sole.

The object is realized by a shoe sole includes a surface layer and a base layer, the surface layer is attached to the upper surface of the base layer; a shaped hole formed through the base layer, an air permeable portion filled in the shaped hole; the air permeable portion is integrally combined to the base layer as a whole.

A woven material based surface layer is combined to an EVA based base layer by gluing, the outer circle of a PU based air permeable portion is glued together with the inner circle of the shaped hole integrally as a whole.

After adopting the structure as mentioned above, an air permeable portion is secured and adapted to the base layer. Thus the air permeable portion enhances the air permeability of a shoe sole. Moreover, the foot of the user will keep dry and more comfortable via the air permeable portion. At the same time, a shoe sole with air permeable portion can be endured longer lifetime in use, PU processing through hardened treatment has stable structure and avoid itself from deformation. Furthermore, the present invention only provides part of air permeable portion on the shoe sole. The material cost can be saved to increase the competitive ability of products in market promotion.

BRIEF DESCRIPTION OF DRAWING

FIG. 1: is a schematic view of the structure of the present invention.

FIG. 2: is an exploded view of the first embodiment of the present invention.

FIG. 3: is a schematic view of the structure of the second embodiment of the present invention.

FIG. 4: is a schematic view of the structure of the third embodiment of the present invention.

EMBODIMENTS OF THE PRESENT INVENTION

The description is described according to the appended drawings hereinafter.

Referring to FIG. 1 and FIG. 2, the present invention includes a surface layer 1 and a base layer 2. The surface layer 1 is made of woven material. And the surface layer 1 is attached to the base layer 2 by gluing or adhering. A shaped hole 21 is formed through the base layer 2. The hole 21 is located at the middle portion of the base layer 2. An air permeable portion 22 is filled in through the location of the shaped hole 21. And the air permeable portion 22 is combined to the base layer 2 integrally as a whole with better air permeability. The concrete structure of them is: PU based air permeable portion 22 has a rim or outer circle adhered to an inner circle of the shaped hole 21 integrally as a whole.

The base layer 2 is made of EVA material, while the air permeable portion 22 is made of PU, which is located at the middle portion of the base layer 2. Manufacturing method of the base layer 2 is described as following. First of all, processing an EVA based plastic, and then cutting a portion of the EVA based plastic into the shape of a shoe sole, trims a shaped hole in the middle of the cut open portion (i.e. EVA based base layer). Thus a shaped hole is formed through the cut open portion thereof. After the shaped hole is shaped, by means of injection molding injects PU material, which is processed with hardened treatment before injection, into the shaped hole 21 to form an air permeable portion 22. Through the process of injection molding, the air permeable portion 22 is secured to the base layer 2 integrally as a whole. Finally, the surface layer 1 is attached to an upper surface of the base layer 2. The manufacturing process of the present invention is thus as described above.

After incorporated with such PU material, the middle portion of the sole has an air permeable portion 22 with improved air permeability. The foot of the user can keep dry and more comfortable for an air permeable portion 22 formed through the sole. The air permeable portion 22 keeps a stable structure without deformation due to the PU is pre-processed through hardened treatment. Thus the present invention has a prolonged lifetime in practice. And, in the present invention, the material cost is saved. Only partly adopts the PU based air permeable portion 22 incorporated into the middle portion of the base layer 2. That is, the permeable portion 22 only formed through the middle portion of a sole, which is endurable for men's foot to slip-on, to exert his foot pressure strength and sweat. But the EVA based material is adapted to the sole portion around the rim of the permeable portion to guarantee the quality of the mass production of the present invention, the capital investment plan for the present invention is cost effective. The manufacturer can promote the products with competitive ability in market.

Referring to FIG. 3, a second embodiment of the present invention is illustrated, as shown, the present invention can be applied to kinds of all sizes and styles of shoes.

Referring to FIG. 4, based on the prior embodiments, a third embodiment of the present invention is illustrated as shown. A number of improved air permeable shaped holes 21 are illustrated as shown. In that, holes 21 are formed through the base layer 2. Theses holes 21 are placed below the sole and heel of a man's foot. And these air permeable portions are formed through and filled in these shaped holes 21. Adoption of this kind of structure further saves more material cost for manufacturing shoe soles. And improves the products' competitive ability in market promotion. 

1. A shoe sole comprising: A surface layer (1) and a base layer (2), the surface layer (1) is attached to the upper surface of the base layer (2); characteristic in that: A shaped hole (21) formed through the base layer (2), an air permeable portion (22) filled in the shaped hole (21), the air permeable portion (22) combined to the base layer (2) integrally as a whole.
 2. A shoe sole according to claim 1 claimed, in that, a woven material based surface layer (1) is combined to an EVA based base layer (2) by gluing, PU based air permeable portion (22) is glued together with the inner circle of the shaped hole (21) integrally as a whole.
 3. A shoe sole according to the claim 1 claimed, in that, a shaped hole (21) is formed through the base layer (2), the hole is located at the middle portion of the base layer (2).
 4. A shoe sole according to the claim 1 claimed, in that, a plurality of shaped holes (21) are formed through the base layer (2), the holes (21) are placed below the sole and heel portion of man's foot respectively. 